Machine-gun.



C. A. NELSON.

MACHINE GUN. APPLICATION FILED Aus. I6. IsIe.

Patented Feb. 19, 1918.

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UNITED STATES PATENT OFFICE.

CHARLES A. NELSON, 0F UTICA, YORK, ASSIGNOR T0 SAVAGE ARMS CORPORATION, A CORPORATION OF DELAWARE.

MACHINE-GUN.

Specification of Letters Patent.

Patented Feb. 19, 1918.

Application led August 16, 1916. Serial No. 115,127.

To all whom it may concern.'

Be it known that I, CHARLES A. NELSON,

na citizen of the United States, and a resident of Utica, Oneida county, State of New York, have invented certain new and useful Improvements in Machine-Guns, of which the following is a full, true, and complete specication.

This invention is an improvement in gas operated machine or similar automatic guns and relates more particularly to the agents whereby the gas pressure of the explosion is utilized for the operation of the loading mechanism. Merely as an example of a gun having such agents I refer to the well-known Savage-Lewis machine gun in which there is employed a gas-impelled rod or plunger mechanism formed of two sections connected together in alinement, one constituting a plston rod and piston subject to the gas pressure escaping laterally from the barrel, and the other section being a motion transmitting and motion distributing member serving to actuate the several parts of the loading and other mechanism. As said member moves under the pressure of the gas imparted to it through the piston rod, it acts through a cam-slot, or otherwise, to rotate the breech bolt and unlock it and to carry it rearwardly against spring pressure until the empty shell is ejected, and immediately following ejection, the spring ressure returns the said member, Aand during the return movement a new cartridge is placed in the chamber of the barrel, the breech bolt being automatically restored and locked in its restored position and the firing pin being cocked or cocked and immediately released, according to whether the trigger is held pulled during the gas operation. Other parts are likewise actuated by and during the reciprocation of the said section. But, although I have made my invention primarilyas an improvement on the said Savage-Lewis gun, it is also applicable for use in connection with any other type of gun or apparatus where the same, or similar parts, or a similar cycle is performed, and the features characterizing my invention are, therefore, broadly claimed below.

The immediate object of the invention is to avoid or prevent fracture of the reciprocating plunger mechanism in the vicinity of the joint or junction between the piston rod proper and the part or section actuated by it. These parts for certain reasons are required to be disconnectible, and in the gun referred to, aswell as innothers operating on the same principle, calizes at the region of the attachment and fracture of the piston rod, due to crystallizationof the metal, has heretofore frequently resulted attended, of course, with disablement of the gun. Reinforcement of the joint in the region of fracture, as by the use of thicker cross-sections, is not a remedy and is moreover forbidden in any substantial degree by the condition that these guns must be as light as possible so as to be capable of use as a shoulder arm.

I have discovered that I can eliminate the cause of breakage, without thicker metal, by connecting the two sections with a loose joint and` a spring for controlling the joint, by which means I retain the sections in proper relative positions, prevent any material endwise movement and prevent localization of the injurious stresses in either of the sections and especially at the place where fracture is most likely to occur. In its improved and preferred construction as herein shown, the loose joint permits a certain relative rotary movement between sections while the spring controlling member, preferably a helical spring, tends to prevent and restrain such movement, and the arrangement is ,such that disconnection of the sections can be accomplished very readily and without the use of tools.

In the accompanying drawings I have illustrated one form of my invention incorporated in the Savage-Lewis machine gun above alluded to.

Figure 1 is a central longitudinal section a condition of stress l-'' of this gun, certain portions not relating to i yielding member employed in said connection.

In these drawings the gas-operated plunger mechanism comprlses a piston rod secv usual bayonet lugs in the wall of or'pr'ovided with cam surfaces 21 and 22 so tion in the receiver whereby it tion and a motion-transmitting section- 11. The piston rod section 10 has a piston head 12 at its end and is mounted to slide in a cylinder 13 secured to the gun barrel 14 and in communication therewith through a vent 15 forward of the piston head. The motion- -transmitting section 11 is connected to the piston section by the loose joint and spring presently described, and is mounted to slide partly within the cylinder 13 and partly in a slideway formed in the receiver of the on which the barrel and many of the other arts of the gun are mounted. The breech Eolt 16, mounted to slide and also to rotatein the receiver, and provided with the forV locking with the breech, is the principal member directly operated by the section 11. In its central chamber `17 it contains the striker or rin pin 18, and the latter is connected to the post 19 on the section 11, through a slot 20 the bolt. rThis slot is curved that when the post approaches one end of the slot,`it rotates the breech bolt in one direction and as it leaves this end of the slot reverses the rotation and thereby performs the function of lookin and unlocking the bolt as Will be understoo The sectional contour of the section l1 is designed to hold it to a non-rotary movement of reciproca# may properly described. On with a row of rotate the breech bolt as just its lower side it is formed rack teeth 23 accommodated the receiver and engaged with a springbarrel gear-wheel 24. The spring actlng on this gear tends to rotate it 1n the direction to restorey the section 11 and the piston rod to their forward position. Each gasimpelled rearward motion of the piston takes place against the spring, tension of the latter controls the rapidity of fire which in practice is very rapid. The drawings show the sear and trigger combination and certain other parts which will Je recognized without further description. Ihese have no direct relation to my invenzion, which, as above stated, is concerned vith the integrity of the junction-between yhe piston rod and the rack member from vhich the breech bolt, firing pin and other )arts receive their motion.

The joint between the piston and the rack member has heretofore been made by crossinning the former in a socket end in the itter and also by other forms of positive nd more or less rigid connections intended n provide maximum security, though in ractice ineil'ectual for that purpose.l If the )int itself withstandsthe strain of rapid ring, the fracture tends to occur in the pis- )n rod just in advance of the joint, and ue in my opinion to the lack of accommodaon in the latter.

in a groove in and the adjusted i In the new, joint the socket in` the end of the rack-member is retained and the piston rod is screw-threaded into it, preferably with square threads andrather loose, as intended to be shown at 25 in Fig. 5. The governing spring 26, separately shown in Fig. 6, is placed on the rod between a collar or shoulder 27 thereon and the end of the socket, with its out-turned ends 28 seated in notches 29-and 30, respectively in the socket end and collar.- This assemblage may be accomplished by holding one end of the spring out of its'notch while the rod is being screwed into the socket and allowing it to seat in its notch when the rod is in place. In the normal relation it is intended that the Spring be free from distortion so that it will tend to resist relative rotation of the parts in either direction, and so that it will restore them to normal if momentarily displaced. Preferably, the pitch of the threads is so related to the pitch of the coils of the spring that rotation of the piston rod in a direction to screw it out of the socket will contract the spring against the rod and further rotation will be thereby prevented, while rotation in the opposite dlrection,l will tend to squeeze the coils of thespring between the collar 27 and the end of the socket, which eventually forms a Vpositive limit to such reverse rotation. Thus, the spring itself may constitute a stop for limiting the relative rotation of the parts in either direction from normal, but other means may be provided for preventing ac? cidental separation, where springs -of different form or in different relation are used f for governing the positions of the jointed parts. The helical form Iof spring is preferred for the gun in questiton because of its simplicity and ease of assemblage with the screw-type of connection, and the said type of connection is preferred because it is readily disconnectible while providing maximum surface to withstand the thrust. 'p Disconnection-is accomplished by lifting one end of the spring and unscrewin the rod, no tools being required. It Will e apparent however, that the sections can be connected in proper thrust-sustaini g relation by other means if desired, so long as their relative positions are subject to the control of the spring. My invention is thus not confined to the specific joint illustrated, although the features thereof constitute important adjuncts to the principle thereof. I clainl- 4 l. A gun having gas-operated plunger mechanism including a piston section, a motion-transmittingr section, connections for preventing relative longitudinal movement ofthe sections, and a spring permitting but resisting relative rotary movement.

2. Plunger mechanism for automatic,

actuing ating section, a reciprocating piston section, a detachable connection for longitudinally operating one by the other, and resilient means interposed between the said sections adapted to resist relative rotary movement therebetween.

3. Plunger mechanism for automatic discharge-actuated guns, including a piston rod section, a mechanism-actuating section, a connection therebetween whereby the one may impart longitudinal movement to the other, and spring means tending to prevent relative rotary moveme 't between said sections.

4. In apparatus of the kind described the combination of two reciprocating powertransmitting sections, sub]ect to rapid endwise vibration and connected to each other by screw-type engaging means and spring means, yieldingly resisting relative rotary movement between said sections in either direction.

5. In apparatus of the kind described, the combination of two reciprocating powertransmitting sections subject to rapid endwise vibration and connected to each other by means permitting relative rotary movement therebetween, and spring-means resistsuch movement and providing a positive limit thereto.

6. In apparatus of the kind described, a rod section, a mechanism actuating section, a screw-threaded connection between said sections, and a coil spring restraining relative rotary movement of said sections.

7. In guns of the kind described, a piston section, a mechanism actuating section, a

screw-threaded connection between said sections, and a coil spring tending to prevent relative rotary movement of said sections and positively limitingl the extent of such rotary movement in eit er direction.

8. An actuating rod including two sections having loose threaded connection with each other, and a coil spring encircling one section, slightly larger than the portion encircled and having one end connected to each section. Y

9. An actuatin means Jfor automatic machine uns, inclu ing a piston section, a bolt actuatlng section, and means for preventing the transmission of excessive Vstress to the piston rod section comprising a loose threaded connection between said sections and a coil spring loosely encircling one section and having one end connected to each section.

10. A reciprocating plunger mechanism including two sections, one of said sections havin one end threaded into one end of the ot er, and a coil spring encircling one of said sections adjacent to the other section and of slightly larger diameter than the portion encircled and having its opposite ends connected to the two sections, the pitch of the screw threads and of the spring coils being such that a relative rotation of said sections in one direction is limited by the contraction of the spring against the part encircled, and relative rotation in the opposite direction is limited by the endwise compresson of the coils of the spring.

In testimony whereof, I have signed this specification.

CHARLES A. NELSON. 

